debug: add gdb backtrace on segfault for embed tests

Author: Qard

.github/workflows/build.yml

@@ -226,4 +226,8 @@ jobs:
           echo "LLVM_CONFIG_PATH=${{ runner.temp }}/llvm-${{ env.clang }}/bin/llvm-config" >> $GITHUB_ENV
 
       - name: Test with embed feature
-        run: cargo test --workspace --release --features closure,embed,anyhow --no-fail-fast
+        run: |
+          sudo sysctl -w kernel.core_pattern='core.%e.%p'
+          ulimit -c unlimited
+          cargo test --workspace --release --features closure,embed,anyhow --no-fail-fast || \
+            (for core in core.*; do [ -f "$core" ] && gdb -batch -ex "thread apply all bt" target/release/deps/sapi_tests-* "$core"; done; exit 1)